Thomas J. Wandless and colleagues from Stanford University provide detailed instructions for "Regulating Protein Stability in Mammalian Cells Using Small Molecules." This technique provides a rapid, reversible, and tunable method for studying the activity of a protein of interest in cells. The protein is attached to a destabilization domain, and the resulting fusion proteins are unstable and degraded, except in the presence of small ligands. The speed of small-molecule binding makes it an attractive alternative to studying gene function using RNA interference (RNAi). The method is freely accessible on the website for Cold Spring Harbor Protocols.
The second featured article for March looks at long-range chromosomal interactions and the proteins that mediate them. Stephen Baylin and colleagues from Johns Hopkins University contribute a method for the "Combined 3C-ChIP-Cloning (6C) Assay: A Tool to Unravel Protein Mediated Genome Architecture." 6C technology combines multiple techniques to identify the proteins that bridge distant genomic regions, while simultaneously identifying physical proximities. The method is also useful for determining if a candidate protein might mediate long-range interactions, both in cis and in trans in the nucleus. The 6C assay advances our understanding of chromatin folding and provides an important tool to examine the role of specific proteins in nuclear organization. This method is freely accessible on the website for Cold Spring Harbor Protocols.
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Tuberculosis hides in cells so the antigens are not recognized by the immune system. The BCG vaccine also does the same thing, as previously reported in The Journal of Immunology in 2006 by Jagannath and Christopher Singh, a doctoral student at The University of Texas Graduate School of Biomedical Sciences at Houston.
"Dr. Jagannath hypothesized that a drug, rapamycin, which modulates the movement of particles in cells, would cause BCG antigens to enter pathways leading to improved immunization," Hunter said. "In addition, Dr. Jagannath had previously demonstrated that genetic deletion of the fpbA gene has similar effects."
Rapamycin is a drug used to fight cancer and inflammation. In 1992, the Organ Transplantation Center at the UT Medical School was first to conduct rapamycin clinical trials. The UT group led by Barry D. Kahan, M.D., Ph.D., now professor emeritus, showed that rapamycin significantly reduces the frequency of acute kidney transplant rejection.
"Our findings break new ground in vaccine research in general and make improvements for antituberculosis vaccines in particular, because they provide a simple and powerful strategy to enhance vaccine efficiency," the researchers wrote in the paper. They now plan to add additional antigens to the BCG vaccine to further improve its effectiveness before clinical trials.
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